Turbulent convection in subglacial lakes

Subglacial lakes are isolated, cold-temperature and high-pressure water environments hidden under ice sheets, which might host extreme microorganisms. Here, we use two-dimensional direct numerical simulations in order to investigate the characteristic temperature fluctuations velocities freshwater subglacial as functions of overburden pressure, $p_i$, depth, $h$, geothermal flux, $F$. Geothermal heating is unique forcing mechanism consider a flat ice-water interface. fully convective when $p_i$ larger than critical pressure $p_*\approx 2848$ dbar, but self organize into lower bulk an upper stably-stratified layer $p_i < p_*$, because existence at low density maximum $T_d$ greater freezing $T_f$. For both high demonstrate that Nusselt number $Nu$ Reynolds $Re$ satisfy classical scaling laws provided effective Rayleigh $Ra_{eff}$ considered. We show layers dynamically decoupled leading plume penetration weak induces limited entrainment stable fluid. From empirical power law equation for with $Ra_{eff}$, derive two sets closed-form expressions variables interest, including unknown bottom temperature, terms problem parameters $h$ The predictions correspond limiting regimes obtained thermal expansion coefficient either approximately constant or linearly proportional difference driving convection.